1. Technical Field
The present invention relates to a printing system and a printing method, and relates more particularly to a printing system and printing method for printing on roll paper.
2. Related Art
Roll paper is used as the print medium in receipt printers that are typically used in cash registers for example. When printing on the roll paper the printer prints one or multiple lines at a time and then cuts the roll paper when a paper cutting command is asserted after verifying that printing has ended. Printing to roll paper at a cash register therefore enables using roll paper without leaving wasted white space.
Printers that print by moving the print head in a main scanning direction while advancing the paper in a sub-scanning direction include a plurality of nozzles arranged in both the main scanning direction and sub-scanning direction on the print head. Printing occurs by discharging ink from the nozzles. One method of processing the print data in this type of printer is described next.
The print data is converted to raster data for each raster in the main scanning direction and the raster data is allocated to one horizontal line (raster) of nozzles (that is, one row of nozzles in the main scanning direction). Raster data is similarly assigned to all nozzle rows of the print head to generate one set of data referred to herein as “partial print data.” This partial print data is then printed in one unit by the print head.
When this type of printer is used to print roll paper, there are cases in which there is not enough raster data for all nozzle rows on the last pass of the print head (that is, when printing the last set of partial print data) and white space is left in the area covered by the nozzles for which there is no raster data. In this case the printer prints the last batch of partial print data containing and then advances the paper a distance including the white space. The roll paper is then cut after the white space. The white space corresponding to the blank raster data left on the roll paper is waste.